What is the difference between speed and velocity?

Speed is how fast an object moves and is a scalar quantity with size only. Velocity is the speed in a stated direction and is a vector with both size and direction. Two objects can have the same speed but different velocities if they are moving in different directions.

What does each of Newton's three laws say?

Newton's first law: an object stays at rest or at constant velocity unless a resultant force acts. Newton's second law: the resultant force equals mass times acceleration, F = ma. Newton's third law: when two objects interact they exert equal and opposite forces on each other.

What is the difference between mass and weight?

Mass is the amount of matter in an object, measured in kilograms, and is the same everywhere. Weight is the force of gravity on an object, measured in newtons, and depends on the gravitational field strength, so weight = mass times g, where g is about 10 N/kg on Earth.

What affects the stopping distance of a car?

Stopping distance is the thinking distance plus the braking distance. Thinking distance increases with speed, tiredness, distraction, alcohol or drugs. Braking distance increases with speed, a wet or icy road, worn tyres or brakes, and a heavier load. Braking distance grows more steeply with speed than thinking distance.

EnglandCombined Science

Edexcel GCSE Combined Science CP2 Motion and forces: a complete overview of speed, acceleration, Newton's laws and stopping distances

Q: What does Edexcel Combined Science CP2 cover?

CP2 covers distance, displacement, speed and velocity, the equations for speed and acceleration, the uniform acceleration equation, distance-time and velocity-time graphs, contact and non-contact forces, resultant forces, Newton's three laws of motion, the equation F = ma, the difference between mass and weight, and stopping distances.

A deep-dive Edexcel GCSE Combined Science guide to Topic 2 (CP2) Motion and forces. Covers distance, displacement, speed and velocity, the equations for speed and acceleration, the uniform acceleration equation, distance-time and velocity-time graphs, contact and non-contact forces, Newton's three laws, F = ma, mass and weight, and stopping distances.

Generated by Claude Opus 4.814 min readCP2Updated 2026-06-02

Reviewed by: AI editorial process; not yet individually human-reviewed

Jump to a section

What CP2 actually demands
Describing motion
Forces and Newton's laws
How CP2 is examined
Check your knowledge

What CP2 actually demands

Motion and forces is one of the most calculation-heavy topics on Physics Paper 1. The examiners reward confident rearranging and substitution into the motion equations and $F = ma$ , correct interpretation of motion graphs, and the factors affecting stopping distance.

This guide walks through the two halves of the topic and ties together the matching dot-point pages, each with its own practice questions.

Describing motion

Speed is distance per unit time (scalar); velocity is speed in a direction (vector). The key equations are:

v = \frac{x}{t}, \qquad a = \frac{v - u}{t}, \qquad v^2 - u^2 = 2as

On a distance-time graph the gradient is the speed; on a velocity-time graph the gradient is the acceleration and the area under the line is the distance.

Forces and Newton's laws

A force is a push or pull in newtons. Contact forces need touching (friction, tension); non-contact forces act at a distance (gravity, magnetism). The resultant force is the net of all forces.

Newton's first law: no resultant force means rest or constant velocity.
Newton's second law: $F = ma$ .
Newton's third law: equal and opposite force pairs.

Mass (kg) is constant; weight $W = mg$ (N) depends on gravity. Stopping distance = thinking distance + braking distance.

How CP2 is examined

Calculations. Speed, acceleration, $v^2 - u^2 = 2as$ , and $F = ma$ .
Graphs. Reading gradients and areas from motion graphs.
Laws. Stating and applying Newton's three laws.
Stopping distance. Listing the factors that affect each part.

Check your knowledge

A mix of recall and calculation questions covering CP2. Attempt them under timed conditions, then check against the solutions.

State the difference between speed and velocity. (1 mark)
Write the equation for acceleration. (1 mark)
On a velocity-time graph, what does the area under the line represent? (1 mark)
State Newton's second law as an equation. (1 mark)
A 2 kg object has a resultant force of 10 N. Calculate its acceleration. (2 marks)
State the difference between mass and weight. (2 marks)
Calculate the weight of a 6 kg object on Earth (g = 10 N/kg). (2 marks)
State the two parts that make up stopping distance. (1 mark)

Sources & how we know this

Edexcel GCSE (9-1) Combined Science (1SC0) specification — Pearson (2016)